The present invention relates to a vessel for bulk materials, whose level can be continuously determined from outside during the filling or emptying process.
In general, the level of bulk materials in upressurized vessels can be read directly from a measuring rod or, in the case of pressurized or thermally loaded vessels, from an inspection glass. In both cases the remote transmission of the directly read measured values is difficult to implement. To avoid these drawbacks, an indirect measuring method can be used. In this case, the attention of X-radiation or radioactive radiation in the bulk material is used to determine its level. In the latter case, remote transmission can be implemented without major difficulty, but this require extensive safety measures in addition to structural modifications of the vessel to adapt it for the respective transmitters and receivers.
The object of the present invention therefore is to develop a vessel for bulk materials which permits rapid and defined remote monitoring of the level of filling without requiring structural modifications.
This object can be achieved according to the present invention by providing, a generic term for devices which change mechanical/electrical energy in response to sonic and ultra sonic frequencies, at least one AE (acoustic emission) transducer at each of the levels defining full and empty states of the vessel and by providing at least one acoustic waveguide at the wall of the vessel between the two AE transducers defining full and empty levels, and by connecting the AE transducers with an electronic signal processing unit.
The wall of the vessel advantageously serves as an acoustic waveguide. The external wall of the vessel is provided with at least two AE transducers at the upper and lower ends of the region to be monitored, and the friction noises generated by the moving bulk materials at the wall of the vessel are carried by the vessel, as a waveguide, to the two transducers, the signals are evaluated as AE signals by means of the connected electronic signal processing unit. The movement of the bulk material can thus be determined by localization from the difference between the arrival times of the signals detected by the two AE transducers. The individual locations are represented in a histogram or a pulse summation curve. The start or the end of the histogram or of the pulse summation curve indicates the level of the bulk material during filling or emptying of the vessel. The level indication which is generated by the moving bulk material and stored can be recalled in the state of rest of the bulk material.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific example, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.